1. Field of the Invention
The present invention relates to an engine starter drive for an internal combustion engine and, more particularly, to an engine starter drive for a starter of the positive shift type wherein the starter motor pinion travels under inertia to engage the flywheel ring gear of the engine to be started, such a starter having a solenoid at one end of the housing of the starter to energize the starter motor.
2. Description of the Prior Art
Heretofore, co-axial solenoid type starter motors which utilize a solenoid to advance a shaft with a drive pinion have been known in the art. U.S. Pat. No. 3,210,554 (A. H. Seilly, et al) shows the use of a solenoid to attract an armature to overcome the force of the spring and move a sleeve forwardly by an amount sufficient to engage the teeth of a pinion with the teeth of a flywheel. When the armature has completed its travel a switch is closed to start the motor. When the pinion is fully engaged with the flywheel, catch balls move into recesses and are held therein by a collar. When the engine is started, the remotely disposed switch is opened and the armature returns to its original position under the action of the spring.
U.S. Pat. No. 3,124,694 (A. H. Seilly) shows a starting mechanism with an axially movable core to impart initial axial movement to the shiftable drive portion. U.S. Pat. No. 3,177,368 (A. H. Seilly) discloses an engine starting mechanism with internal switching so that if the starter switch is held closed after the engine has started, when the speed of the motor exceeds a predetermined value, a resilient member will overcome the action of the solenoid winding so that the pinion is withdrawn from engagment with the ring gear and the motor switch is opened to break the circuit to the motor. U.S. Pat. No. 4,156,817 (K. Preece, et al) shows a starter motor arrangement which utilizes a two-stage starter arrangement to insure clearance of a tooth abutment prior to the engagement of the starter motor.
It is also known to utilize a starter drive which advances the drive pinion on helical splines by inertia developed by the motor. U.S. Pat. No. 3,465,353 (Buxton, et al) discloses a starter drive mounted on a motor drive helical screw shaft to advance the drive pinion. A resilient or spring loaded friction connection with the housing provides a force component axially translating the drive of the screw shaft into a cranking position whereby it engages an engine flywheel. After permanent ignition has occurred and the ignition switch has been released, voltage is applied to an electromagnet to close a switch and short circuit the armature, an action which causes a powerful braking effect to be applied to the starting motor. This braking effect quickly and sharply disengages the shiftable portion of the starter drive. U.S. Pat. No. 4,366,385 (J. O. Williams), which is owned by the Assignee of the present application, shows an engine starter drive in which a screw sleeve mechanism cooperatively engages a helical thread portion on a motor driven shaft. A ring armature member is centrally disposed relative to the screw sleeve mechanism and is connected to the screw sleeve mechanism. When the screw mechanism and the drive pinion are advanced by inertia, a ring armature mechanism is engaged by an engaging member such that the drive member is held in mesh with the engine ring gear and the motor torque is transmitted to the ring gear until the motor is deactivated. However, the starter motor of Williams requires an external solenoid or switch to initiate operation of the starter motor. This requires additional wiring and parts, thereby causing added expense.